Advances in Computing

[waltky]

Mebbe dey took off when the other guy wasn't lookin'...

Deutsche Telekom claims record data transfer record
6 March 2012 - Deutsche Telekom says the innovation will allow it to upgrade its networks without digging up cables

Deutsche Telekom says it has set a new data transfer speed record over a long distance and outside a laboratory. The German firm says it achieved a usable bit rate of 400Gbps (gigabits per second) over a single channel of its fibre optic network. That is more than double the 186Gbps record set by researchers in the US and Canada last year. The company says it now plans to roll out the technology to ensure users can enjoy an "unclogged" service. The experiment was carried out by sending data along the company's network between Berlin and Hanover and back again - a total distance of 734km (456 miles).

The experiment delivered a maximum 512Gbps down each channel, of which 400Gbps was usable data - the spare capacity is used to provide error correction. That is the equivalent of being able to transmit 77 music CDs simultaneously within a second. Each optical fibre is thinner than a human hair but can carry a total of 48 channels - making the total potential throughput up to 24.6Tbps (terabits per second) - or the equivalent of 3,696 CDs per second.

Software upgrade

The firm says the feat was achieved by working with Alcatel Lucent to create new technologies which were installed in its terminal stations at either end of the fibre. Much of the speed gain was delivered through improvements to the software used for forward error correction - a technique that encodes and then decodes the data, allowing a limited amount of corrupted bits to be corrected without the need for the information to be resent.

"You can imagine it as squeezing and tilting the entire set-up around to get more capacity out," Deutsche Telekom's T-Labs manager Heinrich Arnold told the BBC. "It means improvements can be carried out without digging up the existing fibre, without massive hardware replacement - that's actually the charm of the thing. "Whenever we can do something where the biggest part of the infrastructure remains untouched, it means great progress becomes possible." Rather than faster broadband speeds, the firm says the key benefit for home users will be be that they notice an "available, open network" that appears to work more efficiently than at present.

BBC News - Deutsche Telekom claims record data transfer record

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$35 computer goes on sale in Britain
March 1 (UPI) -- A credit-card-sized low-cost computer designed to help teach children to code has gone on sale in Britain, its developers say.

The Raspberry Pi is a bare-bones computer created by volunteers mostly drawn from academia and the British tech industry hope the machines could help reverse a lack of programming skills in the country. "It has been six years in the making; the number of things that had to go right for this to happen is enormous," Eben Upton of the Raspberry Pi Foundation based in Cambridge told the BBC. "I couldn't be more pleased."

Sold uncased without keyboard or monitor, the $35 Pi has drawn interest from educators and enthusiasts. The launch of the Pi comes as the Department for Education is considering changes to the teaching of computing in schools with the goal of greater emphasis on skills like programming. "Initiatives like the Raspberry Pi scheme will give children the opportunity to learn the fundamentals of programming," Secretary of State for Education Michael Gove said.

The Raspberry Pi Foundation says it has already produced thousands of the machines using a Chinese manufacturer.

Read more: http://www.upi.com/Science_News/201...-in-Britain/UPI-73051330645260/#ixzz1oOoRDCGz

 

[waltky]

Dat's fast...

'Twisted light' carries 2.5 terabits of data per second
25 June 2012 - The "twist" of the waves within a light beam is a means to carry potentially vast amounts of data

Researchers have clocked light beams made of "twisted" waves carrying 2.5 terabits of data - the capacity of more than 66 DVDs - per second. The technique relies on manipulating what is known as the orbital angular momentum of the waves. Recent work suggests that the trick could vastly boost the data-carrying capacity in wi-fi and optical fibres. The striking demonstration of the approach, reported in Nature Photonics, is likely to lead to even higher rates. Angular momentum is a slippery concept when applied to light, but an analogy closer to home is the Earth itself. Our planet has "spin angular momentum" because it spins on its axis, and "orbital angular momentum" because it is also revolving around the Sun.

Light can have both these types, but the spin version is the more familiar - it is associated with polarisation, or the direction along which light waves wiggle. Polarising sunglasses and many 3D glasses work by passing one polarisation and not another. In many data-carrying applications involving light, more data is packed on to light waves by encoding data streams on different colours of light. But light of each colour can also be made with two different polarisations, meaning twice as much information can fit within the same "bandwidth" - the range of colours that the transmitting equipment is able to process.

Orbital angular momentum, or OAM, on the other hand, has only recently come to the fore as a promising means to accomplish the same trick. The idea is not to create light waves wiggling in different directions but rather with different amounts of twist, like screws with different numbers of threads. Most recently, Bo Thide of the Swedish Institute of Space Physics and a team of colleagues in Italy demonstrated the principle by sending beams made up of two different OAM states across a canal in Venice, an experiment they described in the New Journal of Physics. Eight beams, each with its own "twist", were prepared for the data-rate test. Most data traffic in optical fibres around the world is made up of different data streams on slightly different colours of light, which are split into their constituent colours at the receiving end in a technique called multiplexing. To fully realise OAM's potential, similar multiplexing of different "twists" must be developed. Alan Willner and his team at the University of Southern California, along with colleagues at Nasa's Jet Propulsion Laboratory and Tel Aviv University, have now demonstrated one way to do that.

The team prepared two sets of four light beams, each with a set level of OAM twist, and each of the eight containing its own data stream. The two sets were then filtered to have different polarisations, and arranged into a single beam with four streams at the centre and four in a doughnut-shape around the edge. At the receiving end, the process is undone and the single beam was unpacked to yield its eight constituent beams, together carrying about 2.5 terabits per second. Initial experiments were only carried out over a distance of about a metre, and Prof Willner said that challenges remained for adapting the approach to fibres or for longer-distance transfer.

More BBC News - 'Twisted light' carries 2.5 terabits of data per second